4.
The extent of the exit point being invoked ends,
and control is passed to the target.

The extent of an exit being "abandoned" because it is being passed over
ends as soon as the transfer of control is initiated. That is,
event 1 occurs at the beginning of the initiation of the transfer of
control.
The consequences are undefined if an attempt is made to transfer control
to an exit point whose dynamic extent has ended.

Events 2 and 3 are actually performed interleaved, in the order
corresponding to the reverse order in which they were established.
The effect of this is that the cleanup clauses of an unwind-protect
see the same dynamic bindings
of variables and catch tags as were
visible when the unwind-protect was entered.